What must you use to guard against glare from headlights of vehicles behind you?

Using a day-night mirror is the most effective way to guard against glare from headlights of vehicles behind you. This type of mirror features a special design that can be adjusted to reduce the brightness of headlights at night. When the glare from a vehicle's headlights is detected, the driver can flip the mirror to the night position, which alters the reflection and minimizes the intensity of light that reaches the driver’s eyes.

A regular rearview mirror does not have this capability, providing a consistent reflection that does not address the issue of glare. Window tints are primarily used for privacy and UV protection, but they do not specifically diminish glare from rear headlights. Anti-glare glasses can help to some extent, but they are not a dedicated solution for car mirrors, and their effectiveness can vary. Thus, the day-night mirror offers the most practical and efficient means to enhance visibility and comfort while driving at night with oncoming traffic.